METHOCEL™ is an economical, high-performing polysaccharide thickener. It is a hydroxypropyl methylcellulose (HPMC) polymer derived from wood pulp that exhibits excellent water retention, adhesion promotion, and binding properties. These properties make it the ideal chemical for improving the performance, visual quality, and consistency of building products.
Cement Mortar
In cement mortars, it is critical to ensure good water retention for adequate hydration, which leads to better strength development. Often, the brick and wall substrates that mortar is applied to are highly absorptive to moisture, resulting in water loss from the mortar. Furthermore, the higher sand content of mortar facilitates easier moisture loss to the brick and wall. METHOCEL™ is highly retentive towards water and will mitigate mortar water loss. Thus, adding METHOCEL™ to cement mortars can improve strength and durability.
Typically, the bond strength of sand, lime, and cement mortar is very low. Adding METHOCEL™ can greatly increase bond strength such that the bending tensile and shear strength of mortars can be greatly improved, even when eccentric or horizontal loads are high.
The amount of METHOCEL™ to add should be determined experimentally. METHOCEL™ can serve as an air-entraining agent, so too much will cause too many bubbles in the mortar, reducing its compressive strength.
Ceramic Tile Adhesive
There can be significant differences in the porosity of ceramic tiles, where some are very porous and absorb more water. This can compromise the bonding properties of ceramic tile adhesives, which are greatly impacted by water loss to either the base layer or the ceramic tiles it is bonding. Therefore, water-retaining agents like METHOCEL™ are especially important to mitigate water loss, allowing high bond strength to develop between base layers and ceramic tiles.
This allows for a process improvement where ceramic tiles do not need to be soaked in or sprayed with water prior to applying the tile adhesive. Furthermore, METHOCEL™ creates slurries that are fine and smooth in appearance, making a more uniform and convenient construction product.
Plaster
Workability, plasticity, and initial viscosity are all important properties of cement- or gypsum-based plaster. Even a very small amount of METHOCEL™ will significantly improve these properties since water is critical for developing strength, durability, and appearance in cement- and gypsum-based plasters. Since METHOCEL™ is extremely water retentive, it slows evaporation and water loss from absorption, which provides more hydration to the plaster and allows better mechanical strength to develop. This also contributes to better plaster mix homogeneity and reduces the risk of cracking.
METHOCEL™ also provides lubricity to dispersed particles in plasters, which increases workability and enhances mixing characteristics. This leads to smoother, better-looking finishes. It also improves consistency and rheology in mixes, making spreading easier. METHOCEL™ also increases adhesion to walls and surfaces, preventing sagging in gypsum- and cement-based plasters.
Gypsum-based products
Gypsum products are becoming increasingly popular due to benefits such as light weight, thermal insulation, fire resistance, and the ability to adjust indoor humidity. Finish materials based on gypsum, such as render, have also gradually replaced other materials. To achieve full hydration of gypsum, ensure adequate adhesion, and prevent cracking, these materials must be prepared with an appropriate amount of METHOCEL™ as a water-retaining and binding agent. Typically, a 0.2 wt% of METHOCEL™ is added to significantly improve construction performance, prevent cracking, and make finished surfaces flat and smooth.
Other Building Materials
Concrete: METHOCEL™ can be used as a drag-reducing agent in pipelines and a water-retaining agent in concrete. It can also significantly improve initial setting strength.
Building adhesives: METHOCEL™ serves as the primary adhesive in dry-mix wallpaper pastes to provide the required wet tack to adhere the paper to the wall. Before setting, the adhesive has good slip properties, allowing for easier readjustment. The METHOCEL™ grades used in building and construction applications are soluble in cold water, making formulating easier. They also feature thermal gelation properties, where gelation can be achieved under specific heat conditions. This gelation is useful in plywood laminating adhesives to prevent the adhesive from seeping too deeply into the wood.
Binders and rubber powder used in buildings: Using METHOCEL™ as an auxiliary bonding material improves not only the bonding properties but also the mildew resistance of the binder and RDP (redispersible polymer) powder used in buildings.
Coatings industry: METHOCEL™ has a wide range of applications in the coatings industry. It can be used as a film former, thickener, emulsifier, and stabilizer in latex paints and water-based coatings. It creates films with good abrasion resistance, leveling, and adhesion while improving surface tension, pH stability, and compatibility with metallic pigments. METHOCEL™ provides coating formulations with good storage stability and blends wellwith organic solvents. Since METHOCEL™ functions as a good dispersing media for pigments, it has been widely used in colored coatings, significantly improving their performance and decorative effects. For more information on this topic, check out
this article.
Summary
METHOCEL™ HPMC plays an important role in bonding, water retention, and improving the performance of construction materials. It is used in a wide range of domestic building materials with significant economic benefits and will likely be used in many more applications within the building and construction space.
Recommended METHOCEL™ Grades
| Grade |
Description |
Typical Viscosity
(2% in water at 20°C, mPa·s) |
Applications |
| METHOCEL™ 228S |
White cellulose ether powder
|
5,000 |
Gypsum and cement plasters, masonry mortars, grouts, and tile and block adhesives |
| METHOCEL™ 254 |
White cellulose ether powder
|
32,000 |
Cement plasters, masonry mortars, grouts, and cement-based tile and block adhesives |
| METHOCEL™ J12MS |
White cellulose ether powder
|
10,000–16,500 |
Ready-mix tile adhesives and renders |
| METHOCEL™ J75MS |
White cellulose ether powder
|
60,000–90,000 |
Ready-mix tile adhesives and renders |
| METHOCEL™ 240S |
White cellulose ether powder
|
30,000–50,000 |
Tape-joint compounds |
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